1. Field of the Invention
The present invention relates to take-up reels of the type for storing and paying out an elongated, flexible member such as a cable, rope, hose or the like, and which automatically rewinds the flexible member when it is released.
2. Description of the Prior Art
There are several applications in which a flexible member such as a lift cable, rope, hose, electrical cable, extension cord, grounding cord or the like is wound about a take-up reel for storage when not in use, and which is payed out by unwinding from the take-up reel to the appropriate length as required. An important application of this arrangement is the use of a flexible hose for carrying air, water, oil, grease, and the like from a reservoir to a dispensing nozzle. For example, in the typical automobile service station, air is delivered from a compressor tank through a long tubular hose which is wound around a spring-loaded take-up reel. The air hose is pulled from the reel for use, and at the same time rewind energy is stored in the wind-up spring motor. The wind-up spring motor rewinds the hose onto the reel when the hose is released.
The rewind action accelerates as more and more of the hose is taken up, with the result that the terminal velocity of the hose is quite high and can cause damage to the rewind mechanism or to itself because of the high shock loading which arises. The whipping action which occurs as a result of the uncontrolled rewinding can cause property damage and personal injury. Moreover, during such uncontrolled rewinding, the rapidly rotating reel with its rotational inertia gradually increasing as more and more of the cable is recovered can overrun the spring motor and reverse wind the spring thereby causing deformation or breakage of the spring.
Various braking devices have been proposed for automatically limiting the rewind rate of the take-up reel. In one such arrangement, the movement of a piston which is coupled to the rewind reel is retarded by a volume of liquid which is contained within a cylinder and which is discharged through a flow restriction in response to movement of the piston. Such arrangements have found only limited acceptance because of the interference of the piston at low rewind velocity.